In this paper, we study propagation
modes in nonlinear symmetrical slab waveguides characterized by
a complex-valued n parameter in order
to include gain or loss guiding propagation. Using the Fresnel equation
and applying the finite difference beam propagation method (FD-BPM),
we calculate gain-guided or loss-guided propagation modes in slab
waveguides. Modes calculated numerically are compared with analytical
modes obtained in a recent paper by A. Siegman [1]. |